We need to build a VOIP app using Twilio SDK with the below functionalities. It's just a MVP app as we wanted ensure that we are able to achieve the core functionalities.
1. From the app, I should be able to call all my contacts via Twilio (Virtual number will be shared) 2. When others calls my Twilio number, I want to receive it as VOIP call on my app. 3. All the incoming and outgoing calls must be recorded. (Twilio's out-of-the-box feature) 4. During the call (Incoming / Outgoing), I should be able to see some basic details about the contact. You may need to make an API call to get the basic details. (API will be shared) 5. In Call history screen, I should be able to replay the recorded audio.
I also have attached some mock screens. (Please ignore the video icon.)
Twilio already has an open source app called voice-quickstart-ios. You only need to customise it little bit to meet the requirement. Great if you have experience in Twilio SDK.